10.1 Introduction

The following kinds of activities are included under router O&M:

• Diagnosing hardware problems in the router's processor, in its network interfaces, or in its connected networks, modems, or communication lines.

• Installing new hardware

• Installing new software.

• Restarting or rebooting the router after a crash.

• Configuring (or reconfiguring) the router.

• Detecting and diagnosing Internet problems such as congestion, routing loops, bad IP addresses, black holes, packet avalanches, and misbehaved hosts.

• Changing network topology, either temporarily (e.g., to bypass a communication line problem) or permanently.

• Monitoring the status and performance of the routers and the connected networks.

• Collecting traffic statistics for use in (Inter-)network planning.

• Coordinating the above activities with appropriate vendors and telecommunications specialists.

Routers and their connected communication lines are often operated as a system by a centralized O&M organization. This organization may maintain a (Inter-)network operation center, or NOC, to carry out its O&M functions. It is essential that routers support remote control and monitoring from such a NOC through an Internet path, since routers might not be connected to the same network as their NOC. Since a network failure may temporarily preclude network access, many NOCs insist that routers be accessible for network management through an alternative means, often dial-up modems attached to console ports on the routers.

Since an IP packet traversing an internet will often use routers under the control of more than one NOC, Internet problem diagnosis will often involve cooperation of personnel of more than one NOC. In some cases, the same router may need to be monitored by more than one NOC, but only if necessary, because excessive monitoring could impact a router's performance.

The tools available for monitoring at a NOC may cover a wide range of sophistication. Current implementations include multi-window, dynamic displays of the entire router system. The use of AI techniques for automatic problem diagnosis is proposed for the future.

Router O&M facilities discussed here are only a part of the large and difficult problem of Internet management. These problems encompass not only multiple management organizations, but also multiple protocol layers. For example, at the current stage of evolution of the Internet architecture, there is a strong coupling between host TCP implementations and eventual IP-level congestion in the router system [OPER:1]. Therefore, diagnosis of congestion problems will sometimes require the monitoring of TCP statistics in hosts. There are currently a number of R&D efforts in progress in the area of Internet management and more specifically router O&M. These R&D efforts have already produced standards for router O&M. This is also an area in which vendor creativity can make a significant contribution.